Anemia is defined as a reduction of circulating red blood cell mass which results in the reduced oxygen-carrying capacity of the blood. It can also be defined as a reduction in the hemoglobin concentration of the blood.
Classification of Anemia
There are a lot of ways of classifying anemia.
Based on the underlying mechanism, it can be classified as ;
- Anemia due to blood loss,
- Due to destruction of RBC (Hemolysis), and
- Due to reduced RBC production.
According to alteration in red blood cell morphology, it can be classified as ;
- Normocytic, Microcytic, and Macrocytic based on RBC size.
- Normochromic and Hypochromic based on RBC color.
What are the Causes?
Anemia can be caused due to a lot of reasons. Some of them are
Decreased red cell production due to
- Hematopoietic cell damage- from infection, drugs, radiation, and other similar agents.
- Deficiency of factors needed for heme synthesis (Iron) or DNA synthesis ( vitamin B12 or folate)
Increased red cell loss due to:
- External blood loss
- Red cell destruction (hemolytic anemia)
What are Sign & Symptoms?
Symptoms result from decreased oxygen delivery to tissues, and hypovolemia (in patients with acute and marked bleeding)
- Acute-onset anemia is characterized by cardio-respiratory symptoms (tachycardia, lightheadedness, and breathlessness, and dyspnea on exertion).
- Chronic anemia is characterized by the pallor of skin and mucosa (e.g., conjunctiva), fatigue, malaise, Koilonychia, a spoon-shaped concavity of the nails, angina pectoris especially in patients with coronary artery narrowing caused by atherosclerotic disease. Central nervous system hypoxia causing headaches, blurred vision, and drowsiness.
How to Diagnosis Anemia?
We can use
- RBC count less- than 4.5 X 10¹² cells/L (in male) or 4.1 X 10¹² cells/L (in female)
- Hemoglobin– less than 13.5 g/dL (in male) or 11.5 g/dL (in female)
- Hematocrit– less than 40% (in male) or 35% (in female)
- RBC indices
○ MCV (Mean cell volume) – less than 80fL or greater than 100fL
○ MCH (Mean corpuscular hemoglobin) – normal value is 27-33 pg
○ MCHC (Mean corpuscular hemoglobin concentration)- normal value is 33-37 g/dL.
- RBC distribution width
- Cell morphology
- Reticulocyte count- Under normal conditions, the peripheral blood contains less than 1.5% reticulocytes, but in some anemic patients, their number may be increased.
- Iron supply studies
○ Iron in serum: – largely derived from the storage pool of iron, and it is a good indicator of the adequacy of body iron stores
○ Total iron-binding capacity (TIBC):- depends on serum transferrin, which is approximately 33% saturated with iron.
○ Ferritin, marrow iron content:- depends on intake and loss
Management Overview of Anemia
Management highly depends on the underlying cause of the anemia.
- If there is any nutritional deficiency, nutritional supplementary will be a solution. That includes iron, vit b12, and folic acid supplement.
- If there is decreased erythropoietin production due to chronic renal failure or increased erythropoietin requirement such as in cancer patients, synthetic erythropoietin will be given.
- Hg is less than 7 – blood transfusion is indicated.
- If the cause of anemia is 2rd to other hemolytic diseases, treating that specific cause might be the only management option.